# Python functions for the sprokit project
# The following functions are defined:
#
#   sprokit_add_python_module
#   sprokit_create_python_init
#   sprokit_create_python_plugin_init
#
# The following variables may be used to control the behavior of the functions:
#
#   copyright_header
#     The copyright header to place at the top of generated __init__.py files.
#
# Their syntax is:
#
#   sprokit_add_python_module(name modpath module)
#     Installs a pure-Python module into the 'modpath' and puts it into the
#     correct place in the build tree so that it may be used with any built
#     libraries in any build configuration.
#
#   sprokit_create_python_init(modpath [module ...])
#     Creates an __init__.py package file which imports the modules in the
#     arguments for the package.
#
#   sprokit_create_python_plugin_init(modpath)
#     Creates an __init__.py for use as a plugin package (packages for sprokit
#     plugins written in Python must use one of these files as the package
#     __init__.py file and added to the SPROKIT_PYTHON_MODULES environment
#     variable).

if ( NOT TARGET python)
  add_custom_target(python)
endif()

source_group("Python Files"  REGULAR_EXPRESSION ".*\\.py\\.in$")
source_group("Python Files"  REGULAR_EXPRESSION ".*\\.py$")

# Global collection variables
define_property(GLOBAL PROPERTY kwiver_python_modules
  BRIEF_DOCS "Python modules generated by sprokit/kwiver"
  FULL_DOCS "List of Python modiles build."
  )

###
#
# SeeAlso:
#     kwiver/CMake/utils/kwiver-utils-python.cmake
#
function (sprokit_add_python_module    path     modpath    module)

  _kwiver_create_safe_modpath("${modpath}" safe_modpath)

  set(python_arch)
  set(python_noarchdir)

  if (WIN32)
    if (python_noarch)
      return ()
    else ()
      set(python_install_path lib)
    endif ()
  else ()
    if (python_noarch)
      set(python_noarchdir /noarch)
      set(python_install_path lib)
      set(python_arch u)
    else ()
      set(python_install_path "lib${LIB_SUFFIX}")
    endif ()
  endif ()

  if (CMAKE_CONFIGURATION_TYPES)
    set(sprokit_configure_cmake_args
      "\"-Dconfig=${CMAKE_CFG_INTDIR}/\"")
    set(sprokit_configure_extra_dests
      "${sprokit_python_output_path}/\${config}/${kwiver_python_subdir}${python_noarchdir}/${python_sitename}/${modpath}/${module}.py")
  endif ()

  if( WIN32 )
    # Use shorter (but less descript) paths due to 260 char limit on directories on windows
    set(python_configure_id "${safe_modpath}-${module}")
    set(python_module_id "${module}")
  else()
    set(python_configure_id "python${python_arch}-${safe_modpath}-${module}")
    set(python_module_id "python${python_arch}-${safe_modpath}-${module}")
  endif()

  set(pyfile_src "${path}")
  set(pyfile_dst "${sprokit_python_output_path}/${kwiver_python_subdir}${python_noarchdir}/${python_sitename}/${modpath}/${module}.py")
  set(pypkg_install_path "${python_install_path}/${kwiver_python_subdir}/${python_sitename}/${modpath}")

  if (KWIVER_SYMLINK_PYTHON)
      sprokit_symlink_file_w_uid("${python_configure_id}"
        "${python_module_id}"
        "${pyfile_src}"
        "${pyfile_dst}"
        PYTHON_EXECUTABLE)
  else()
      sprokit_configure_file_w_uid("${python_configure_id}"
        "${python_module_id}"
        "${pyfile_src}"
        "${pyfile_dst}"
        PYTHON_EXECUTABLE)
  endif()

  # Force installation of the test into the tests module
  # FIXME: (there was a merge conflict between sprokit_install/install, which
  # should this be?)
  sprokit_install(
      FILES       "${pyfile_dst}"
      DESTINATION "${pypkg_install_path}"
      COMPONENT   runtime
      )

  add_dependencies(python
    "configure-${python_configure_id}")
endfunction ()


###
# Creates a default __init__.py file for a plugin package in the build
# directory.
#
function (sprokit_create_python_plugin_init modpath)
  _kwiver_create_safe_modpath("${modpath}" safe_modpath)

  set(noarch_suffix)
  if (python_noarch)
    set(noarch_suffix "u")
  endif ()

  set(init_template "${CMAKE_CURRENT_BINARY_DIR}/${noarch_suffix}${safe_modpath}.__init__.py")

  if (NOT copyright_header)
    set(copyright_header "# Generated by sprokit")
  endif ()

  file(WRITE "${init_template}"
    "${copyright_header}\n\n")
  file(APPEND "${init_template}"
    "from pkgutil import extend_path\n")
  file(APPEND "${init_template}"
    "__path__ = extend_path(__path__, __name__)\n")

  sprokit_add_python_module("${init_template}"
    "${modpath}"
    __init__)
endfunction ()
